The ONS analysis found that the difference in income for the richest and poorest households was lower for pensioners than for people who were not retired.

But it added that income inequality increased during the past three decades, particularly during the period between 1977 and 1990.

There has also been a pronounced shift in the source of pensioners' income since 1977.

Money from occupational pensions and annuities accounted for an average of just 18pc of retired people's income in 1977, with the state pension accounting for 53pc.

But by 2007/08, the latest period for which figures are available, the state pension made up only 37pc of the money pensioners had coming in, with occupational pensions and annuities accounting for 36pc.